Then your execution plans are using poor indexes, either because that's all they've got to work with (no correct indexes) or the data distribution makes CBO believe other indexes are better.
Originally Posted by dbasupuser
Increasing buffer pool will not help it search poor indexes any better.
If you've got specific queries/bus fcns performing poorly, As Davey23uk said - trace those fcns - and see what it's doing. This identifies the specific sql. Use explain plan on that to see why. Then see what you can do to influence that specific sql to get a better plan.
"False data can act only as a distraction. Therefore. I shall refuse to perceive you." - Bomb #20